Process for the preparation of ketones and novel insecticides produced therefrom

Abstract

An improved method for the decarbalkoxyation of alkylated beta -keto esters to obtain high yields of ketones. In accordance with the method, decarbalkoxylation of alkylated beta -keto esters is accomplished by heating the esters in the presence of dilute aqueous alkali and an effective amount of a phase-transfer agent. The method produces commercially practical yields of ketone in a manner which is facile, economical and environmentally safe. Novel methylene-linked pyrethroid ketones produced from the improved method exhibit insecticidal activity against various agricultural pests.

We claim: 
     
       1. A compound represented by the general formula ##STR21## wherein R is 2,2-dimethyl-3-(2-methylpropenyl)cyclopropyl; 2,2-dimethyl-3-(cyclopentanylidenemethyl)cyclopropyl; or 1-(4-chlorophenyl)-2-methyl propyl. 
     
     
       2. A compound represented by the general formula ##STR22## wherein R is 2,2-dimethyl-3-(cyclopentanylidenemethyl)cyclopropyl; or 2,2-dimethyl-3-(2,2-dichlorovinyl)cyclopropyl. 
     
     
       3. An insecticidal composition comprising a carrier and an insecticidally effective amount of the compound of claim 1. 
     
     
       4. An insecticidal composition comprising a carrier and an insecticidally effective amount of the compound of claim 2. 
     
     
       5. The compound of claim 1 wherein R is 2,2-dimethyl-3-(2-methylpropenyl)cyclopropyl. 
     
     
       6. The compound of claim 1 wherein R is 2,2-dimethyl-3-(cyclopentanylidenemethyl)cyclopropyl. 
     
     
       7. The compound of claim 1 wherein R is 1-(4-chlorophenyl)-2-methylpropyl. 
     
     
       8. The compound of claim 2 wherein R is 2,2-dimethyl-3-(cyclopentanylidenemethyl)cyclopropyl. 
     
     
       9. The compound of claim 2 wherein R is 2,2-dimethyl-3-(2,2-dichlorovinyl)cyclopropyl.